Binding systems are used in connection with binders, folders, books, notebooks, and the like. A binding system functions to maintain two or more sheets, which may be paper, paper-like sheets, or sheets of any other material, in a bound association with one another. A binding system may also function to maintain such sheets in a bound association one or more cover members, the cover members being optionally bound to the binding system.
Various forms of binding systems are known in the art. For example, typical a spiral binding system includes a thin, coiled, binding wire with coils that pass through holes at an edge of the sheets. A typical ring binding system includes one or more rings or ring-like members, optionally connected to one another by a spine member, that pass through the holes in the sheet edges. An adhesive binding system includes a spine member with an adhesive thereon for adhesively binding the sheets along an edge thereof Other binding systems are known by those having ordinary skill in the art.
A subset of ringed binding systems are disk ring binding systems. In one example thereof, U.S. Pat. No. 5,015,114 discloses a binder ring having a disk shaped central portion, an aperture formed substantially in the center of the central portion, and an annular outer rim formed on the periphery of the central portion. The outer rim includes an arcuately shaped, outer surface configured as an outer segment of a circle, and has an axial width greater than the axial width of a central portion. The paper sheets have die cut perforations on one edge sized to fit about the outer rim of the binder rings. U.S. Pat. No. 5,553,959 discloses a disk ring binding system in which a stack of sheets is bound together using a plurality of disk fastening members insertable into openings of the stack of sheets to retain the sheets in the stack. The disk members have a substantially flat disk-like central surface portion and an enlarged continuous rim portion which extends around the periphery of the central surface portion of the disks. The rim portion extends outwardly in a direction perpendicular to the flat central portions of the disks, and the central surface portion has a radius which is larger than the thickness of a stack of sheets to be bound thereby. U.S. Pat. No. 6,074,152 discloses a binding system for index-books and notebooks, with mutually aligned disks having a double-T cross-section. The edge portion of the sheets receives the disks inserted in seats formed in the sheets. Further examples of disk ring binding systems are disclosed in U.S. Pat. Nos. 6,350,096, 6,364,560, and PCT Patent Application Publication No. WO 2007/060185.
It would be desirable to provide an improved disk ring binding system over those systems known in the art.